All of the patents cited throughout this specification are hereby entirely incorporated herein.
Quaternary ammonium compounds are well known as complexing agents for certain compounds, such as anionic dyes. For example, U.S. Pat. No. 5,059,244, to King, discloses an aqueous solution of anionic dyes and an ethoxylated triethanolamine. This composition is useful as an ingredient within ink formulations and as an agent for temporarily tinting textile fibers. Quaternary ammonium compounds have been disclosed as useful auxiliary agents for printing on fiber materials. For example, U.S. Pat. No. 3,785, 767, to Hildebrand, discloses a pad-steaming process for the continuous dyeing and printing of fiber material with a formulation containing anionic dyes and amine salts. Other pertinent teachings of include U.S. Pat. No. 4,563,190, to Topfl, which discloses a dyeing assistant formulation for anionic dyes containing quaternary ammonium compounds that contain at least one basic nitrogen atom to which are attached at least one polyglycol ether chain; U.S. Pat. No. 4,935,033, to Mosimann et al., which discloses a dyeing method for natural polyamide fibers using reactive dyes and a dyeing assistant agent containing a quaternary ammonium compound; and U.S. Pat. No. 4,369,041, to Dvorsky et al., discloses a technique for printing textiles involving exposing the textile to the action of quaternary ammonium compounds before or during the dyeing or printing with acid dyes. Furthermore, Aston et al., U.S. Pat. No. 5,403,358, discloses a pretreatment composition for ink jet which comprises a quaternary ammonium compound and a reactive dye. Such anionic dyes and quaternary ammonium compounds also find application in other areas, for instance: U.S. Pat. No. 4,459130, to Helling et al., discloses a dye preparation which is consisted of an acid dye and a basic carrier which contains quaternary ammonium or phosphonium groups; and U.S. Pat. No. 5,266,077, to Auten et al., discloses a method for tinting a hydrophilic contact lens through the action of a quaternary ammonium compound as a dye complexing agent.
However, there is no teaching specifically complexing a known ultraviolet absorber with a quaternary ammonium compound to form a more versatile UV absorber, not to mention there is no teaching of such a complex which is substantially free from unwanted salts. The closest prior art, U.S. Pat. No. 5,376,304, to Yamamoto et al., discloses a ceric oxide sol (no UV absorber, but it ultimately performs a UV absorption function) which is basically a complex of an anionic compound which is substantially salt-free and a ceric oxide which is, possibly, further reacted with what may be a quat compound. If such a reaction does take place, patentee does not teach nor fairly suggest the performance of a subsequent post-quat reaction salt removal procedure. Furthermore, patentee's initial salt-free anionic compound is not an ultraviolet absorbing compound; however, the resultant ceric oxide sol does exhibit ultraviolet absorption properties.
It has been found that the complexation of an ultraviolet absorber with a quaternary anmmonium compound and the subsequent removal of substantially all the excess salt (formed from the reaction between the cation of the anionic UV absorber and the counter-ion of the quat) produces a compound which possesses the highly desired and unexpected characteristics such as, merely as non-limiting examples, lower incidences of cracking and improved fogging properties. Traditional UV absorbers, such as benzotriazole and benzophenone derivatives, are present on coated substrates as small organic molecules. When dispersed within coating compositions, such traditional absorbers tend to separate from the coating over time and crystallize within the coating on the target substrate. This potential for recrystallization by the traditional UV absorbing compounds thus would cause disassociation of the coating itself through cracking. Furthermore, standard UV absorbers readily sublimate from substrate coatings and produce "fog" which accumulates on other nearby surfaces. Undesirable lightly opaque films form on such surfaces (i.e., the inside of car windows) after a certain length of time of application of the absorber. Such cracking and fogging both diminish the aesthetics of the subject substrate (such as apparel, or upholstery, or the like) and could produce unwanted films on surrounding surfaces. It has been found that the complexation between an ultraviolet absorber and a quat compound provides a compound, upon further removal of substantially all unwanted salt, will not produce such problematic incidences as cracking or fogging on the coated subject substrate. Also, the inventive complex is easily dispersed and dissolved within any standard UV absorber coating composition. Additionally, the presence of such a quat component unexpectedly provides other benefits including anti-static and anti-microbial properties. Therefore, through the utilization of inexpensive reactions and quaternary ammonium compounds, the cost of providing a non-fogging, anti-static, anti-microbial, uniform film-forming, ultraviolet absorbing compound for myriad substrates can be greatly reduced. Therefore, it has been found that substantially salt-free UV absorber/quaternary ammonium complexes provide a cost-effective method of providing a great deal of highly desirable and beneficial properties to many different substrates.
When placed in a complexing solution, the ultraviolet absorber and the quaternary ammonium show a great affinity for one another such that upon disassociation with their respective cations and/or counter ions, the complexation of the absorber and quat drives the formation of unwanted excess salts comprised of the free cations and counter ions. Once the salts are formed, they are easy to remove through standard filtration, phase separation, or extraction techniques. These salts are generally inorganic in nature, although organic cations and counter-ions may also be present and thus should be substantially removed from the inventive complex. Such a salt removal ensures the absorber and quat will remain in a complex together rather than potentially reacting with free cation and/or counter ion upon disassociation within the resultant UV absorber solution. Thus, the desired properties are obtained with a greater amount of the absorber/quat complex and a much lower amount of residual unwanted salt. The term "substantially salt-free" is thus intended to mean free from such unwanted cation/counter-ion salts.